1. Field of the Invention
The present invention relates to a silver halide photographic light-sensitive element containing a novel magenta color forming coupler.
2. Description of the Prior Art
After exposing a silver halide photographic light-sensitive element to light, the element is developed with an aromatic primary amine developing agent. The developing agent is oxidized by color development and reacts with a coupler to form a dye, thus, a color image being formed. In this system, a subtractive method is generally used for color reproduction, in which blue, green and red colors are reproduced by forming yellow, magenta and cyan color images which are in complimentary relation thereto, respectively. In general, acrylacetamide or dibenzoylmethane type couplers are employed for forming yellow color images, pyrazolone, cyanoacetyl or indazolone type couplers are used for forming magenta color images, and phenol type couplers, for example, phenols and naphthols, are utilized for forming cyan color images.
To produce color photographs, couplers which form dyes are incorporated into a developer or are present in a light-sensitive photographic emulsion layer(s).
A variety of 5-pyrazolone type couplers for forming magenta color images are known. Known substituents at the 3-position of the 5-pyrazolone ring include an alkyl group, an aryl group, the alkoxy groups as described in U.S. Pat. No. 2,439,098, the acylamino groups as described in U.S. Pat. Nos. 2,369,489 and 2,600,788, and the ureido groups as described in U.S. Pat. No. 3,558,319 and an anilino group. 3-Anilino-5-pyrazolone type couplers have often been described in the art since U.S. Pat. No. 2,311,081 (U.S. Pat. No. Re. 22,329) was issued and several improvements therein have been proposed. British Patent No. 956,261 discloses that azomethine dyes obtained from derivatives in which the ortho position of the anilino group is substituted with an alkoxy group or a halogen atom have advantageous spectral absorption properties for color photography in that undesired absorption in the red light region is particularly low.
Specific examples of diffusion resistant couplers which belong to this type and are capable of being incorporated into photographic emulsions are described in U.S. Pat. Nos. 3,930,861, 3,907,571, 3,928,044 and 3,935,015, etc. For example, the couplers described in U.S. Pat. No. 3,935,015 are well known and are 3-(acylaminoanilino)-5-pyrazolones represented by the formula (M) below: ##STR2## wherein D.sub.1 represents an aryl group or a heterocyclic group, D.sub.2 represents a straight chain, branched chain or cyclic alkyl group having 7 to 23 carbon atoms, D.sub.3 represents a splitting off group, and L represents an alkoxy group having 1 to 18 carbon atoms or a halogen atom.
These couplers have the characteristics that the undesired absorption of magenta azomethine dyes obtained upon color formation using the same in the red light region is low, the cut-off of the main absorption is good at the longer wavelength side, and magenta color images having a high color density are obtained because the coupling speed is high, and, further, the solubility in organic solvents having a high boiling point is improved so that, after dissolving these couplers in organic solvents, the couplers are emulsion-dispersed in an aqueous medium in the form of fine colloidal particles and then added to emulsions. However, these couplers have the disadvantages that the degree of yellow staining at the unexposed portion after color development processing is high and this degree of yellow staining is increased upon irradiation with light, and, further, have the disadvantages that color fading of the magenta color images obtained upon color development using these compounds occurs to a marked degree upon irradiation with light and the color balance required for color photography is damaged by exposure to light. These disadvantages become fatal defects for color light-sensitive elements, such as color printing papers and the like. Thus, improved couplers which do not have these disadvantages have been strongly desired.